<!doctype html>
<html>
	<head>
		<meta charset="utf-8">
		<title>飞机大战</title>
	</head>

	<body>
		<div id="stage" style="margin: 0 auto; width: 480px; height: 650px; text-align: center; vertical-align: middle" >
			<canvas id="canvas" style="border:2px solid red;" width="480" height="650">
				不支持画板对象
			</canvas>
		</div>
		<script>
			var canvas = document.getElementById('canvas');
			var ctx = canvas.getContext('2d');
			var enemy = new Image();
			enemy.src = "images/enemy1.png";
			enemy.onload = function() {
				//声明变量s，赋值为85
				var s = 85;
				//平时表现得好，加十分
				s = s + 10;
				//在警告框上显示我的最终成绩
				alert(s);

			}
		</script>
	</body>
</html>